1. Field of the Invention
This invention relates to drainage systems and especially to improvements in catch basins designed to receive surface water runoff and to serve as an initial separation stage for removing contaminants from the runoff.
2. Discussion of Related Art
Catch basins are conventionally used in building areas, roadways, parking lots, etc. where the soil surface has been sealed thereby preventing absorption of water runoff into the soil. The catch basin functions to separate the runoff from matter carried therewith which would ordinarily not readily pass through the sewer to which the catch basin discharge is connected. Various types of catch basins have been suggested for providing this filtering effect. For instance, U.S. Pat. No. 3,038,396, issued June 12, 1962, to Jameson, Jr. et al, discloses a structure for providing liquid drainage directly downward and the upward venting of gas. The Jameson structure includes a relatively large perforated pipe which is supported by a smaller perforated pipe in a hole drilled in the earth and filled with a relatively coarse filtering material within the larger breather pipe and an outer casing of finer filtering material whereby gas can flow upward and be discharged through the coarser filter material and the water can flow by gravity and capillarity downwardly through the surrounding casing of fine filtering material. U.S. Pat. No. 1,108,852, issued Aug. 25, 1914, to Scheuermann, shows a drainage plant for road beds which provides a series of hollow spaces which may be opened and in which the street waters run to the sides, and ooze away in a clarified condition after the solid particles have settled in removable settling boxes. U.S. Pat. No. 1,654,803, issued Jan. 3, 1928, to Griffith, shows a sanitary catch basin wherein the sewer connection is located at a comparatively low level while the outflow from the catch basin may be arranged at a much higher level in order to increase the sediment capacity of the catch basin. U.S. Pat. No. 4,031,009, issued June 21, 1977, to Hicks shows a precast reinforced concrete catch basin including a solid horizontal bottom wall with solid, hollow, cylindrical side walls upstanding therefrom to form a sealed, unapertured, undrained sump receptacle for collecting drain water. The hollow, cylindrical upper half contains leaching openings which extend through from the inside to the outside for discharging cleared water.